Concentration of kyanite



Patented Aug. 17, 1943 UNITED STATES PATENT OFF-ICE CONCENTRATION OF KYANITE Francis X. Tartaron, Mulberry, Fla., assignor, by mesne assignments, to Minerals Separation North American Corporation, New York, N. Y.,. a corporation of Maryland No Drawing. Application February 6, 1942, Serial No. 429,767

' 2 Claims.

The present invention relates to an improved process of concentrating kyanite from its ores by iroth flotation.

In my co-pending patent application, Serial No. 387,667, filed April 9, 1941, which has been The present invention is the result of the further discovery that kyanite may be advantageously concentrated from its ores by pre-treating the kyanite ore with nitric acid or hydrochloric acid and then washing out the acid, and then subjecting the thus Dre-treated ore to froth-flotation concentration with the use of an anionic reagent consisting of a higher fatty acid such as oleic acid as the only flotation agent, possibly with slight amounts of pine oil or other frother at the discretion of the operator.

It is unnecessary to theorize about what the pre-treatment with nitric acid or hydrochloric acid does to the particles of kyanite ore, but the can be used.

In the examples hereinafter described; the ore comprising the feed was obtained from Kyanite Products Corporation. Said feed was 35 mesh and had been substantially deslimed.

The method of analysis used in obtaining the figures given in all of the following tables was the float and sink method using acetylene tetrabromide as the parting liquid. The "float obtained by this method of analysis consisted of quartz and the sink consisted of kyanite and whatever iron minerals that were present. None of the products were assayed for acid-soluble iron. EXAMPLE 1.-Pre-treatment with water.For comparative purposes, a pulp of said kyanite ore was agitated for about three minutes at about" 70% solids, and then washed with water. A pulp of the thus pre-treated ore'was conditioned for about two minutes at about 70% solids with oleic acid (red oil) in the amount of 0.2 lb. and pine oil in the amount of about 0.1 110., both per' ton of dry solids in the feed. The thus conditioned ore was then subjected to froth-flotation treatment in a froth-flotation machine, with the following results :7

I Per cent Per cent Per cent Product weight kyani gz g g Feed... 100. 0 41.3 100.0 Conc 19.0 97.5 44.8 Mid 20.3 64.5 31.7 Tail 60. 7 16. 0 2i. 5

- fact is that for some reason such acid pre-treat- It will be noted that this gave a concentrate having a. grade of 97.5% kyanite, but that the recovery was only 44.8% of the kyanite in the feed.

EXAMPLE 2.-Pre-treatment with n'itric-acid.

A pulp of said kyanite ore, to which had been.

added nitric acid in. the amount of 4 lbs., per ton of dry solids in the feed, was agitated -for about three minutes at about solids, and then washed'with water. A pulp of the thus acid pretreated ore was conditioned with oleic; acid and pine'oil exactly as described in Example 1; and

the thus conditioned ore was then subjected to froth-flotation treatment in a froth-flotation machine in the same manner as before, with the following results:

Comparison: of these results with those of Examplel shows that, while the grade of kyanite concentrate has dropped from 97.5% to 92.1%,

the recovery has increased from 44.8% to 80.9%

of the kyanite in the feed.

EXAMPLE 3.Pre-treatment with hydrochloric acid-A pulp of said kyanite ore, to which hadbeen added hydrochloric acid in the amount of about 4 lbs., per ton of dry solids in the feed,

was agitated for about three minutes at about 70% solids, and then washed with water. A pulp of the thus acid pre-treated ore was conditioned with oleic acid and pine oil exactly as described in Example 1; and the thus conditioned ore was then subjected to froth-flotation treatment in a froth-flotation machine in the same manner as before, with the following results:

Per cent kyanite Per cent weight kyenite recovered Iced 1 It will be noted that in this case the kyanite concentrate had a grade of 95.9%, and that the recovery was 84.1% of the kyanite in the feed.

Thus, the foregoingexamples prove that pretreatment of a kyanite ore with nitric or hydrochloric acid in the manner described, makes it possible to produce a kyanite concentrate of satisfactory grade with a high percentage of recovery, by the use of an anionic reagent consisting of a higher fatty acid such as oleic acid as the only flotation agent; with slight amounts of pine. oil as a frother. v

What is claimed is:

1. A process of concentrating kyanite from its ores which comprises comminuting the ore to suitable particle size, pre-treating the comminuted ore by agitating it in a pulp containingnitric acid, then washing the nitric acid away from the ore, then conditioning the thus acidtreated and washed ore by agitating it in a pulp containing as the only flotation agent an anionic reagent consisting of a higher fatty acid containing at least twelve carbon atoms, and subjecting the thus conditioned pulp of kyanite ore to froth-flotation to separate in the froth a concentrate of kyanite.

2. A process of concentrating kyanitefrom its ores which comprises comminuting the ore to suitable particle size, pre-treating the comminuted ore by agitatingit in a pulp containing hydrochloric acid, then washing the hydrochloric acid away from the ore, then-conditioning the thus acid-treated and washed ore by agitating it in a pulp containing as the only flotation agent an anionic reagent consisting of a higher fatty acid containing at least twelve carbon atoms, and subjecting the thus conditioned pulp of kyanite ore to froth-flotation to separate in the froth a concentrate of kyanite,

FRANCIS X. TARTARON. 

